An eye tracking device for tracking an eye is described. The eye tracking device comprises: a first diffractive optical element, DOE, arranged in front of the eye, an image module, wherein the image module is configured to capture an image of the eye via the first DOE. The first DOE is adapted to direct a first portion of incident light reflected from the eye, towards the image module. The eye tracking device is characterized in that the first DOE is configured to provide a lens effect.

A filter device for an optical sensor, including a hologram having a defined number of holographic functions, which are developed in such a way that the filter device blocks optical radiation that impinges upon the filter device from a defined first solid angle and optical radiation that impinges upon the filter device from a defined second solid angle is able to pass through the filter device.

A method for producing a volume hologram with at least one first area in a first color and at least one second area in a second color includes, providing a volume hologram layer made of a photopolymer; arranging a master with a surface structure on the volume hologram layer; exposing the master using coherent light, wherein light which is incident on at least one first partial area of the surface of the master is diffracted or reflected in the direction of the at least one first area of the volume hologram layer and light which is incident on at least one second partial area of the surface of the master is diffracted or reflected in the direction of the at least one second area of the volume hologram, and wherein the light diffracted or reflected by the first and second partial areas differs in at least one optical property.

A phase transformation device may include a solid photosensitive material having a planar input facet and one or more reflective holographic phase masks (RHPMs) within a volume of the solid photosensitive material, where a particular one of the one or more RHPMs is formed as a periodic refractive index variation of the photosensitive material along a particular grating vector and further with a particular non-planar lateral phase profile, where at least one of a period of the refractive index variation along the grating vector or an orientation of the grating vector for each of the one or more RHPMs are arranged to reflect via Bragg diffraction light incident on the input facet that satisfies a Bragg condition, and where a phase distribution of the reflected light from a particular one of the one or more RHPMs is modified by the associated non-planar lateral phase profile.

A display module includes an image light generation device configured to generate image light, a first reflection section configured to reflect the image light from the image light generation device, a first diffraction element configured to diffract the image light entering a first incident surface, a second reflection section configured to reflect the image light from the first diffraction element, and a second diffraction element configured to diffract the image light entering a second incident surface, thereby forming an exit pupil. When viewed from a normal line direction of a virtual plane including a normal line of the first incident surface and a normal line of the second incident surface, an optical axis of the image light from the image light generation device toward the first reflection section and an optical axis of the image light from the first diffraction element toward the second reflection section intersect each other.

A duplex wideband grating includes a first diffraction element and a second diffraction element. The first diffraction element and the second diffraction element may reside in a single volume or in two separate volumes. The first diffraction element may include a first set of Bragg planes, and the second diffraction element may include a second set of Bragg planes. The first diffraction element may be designed to have a peak diffraction efficiency at a first wavelength, and the second diffraction element may be designed to have a peak diffraction efficiency at a second wavelength different from the first wavelength. The first diffraction element and the second diffraction element may be designed to achieve a same angle of dispersion between wavelengths. The duplex wideband grating may have a broader bandwidth with higher average diffraction efficiency across the broader bandwidth than either the first diffraction element or the second diffraction element.

Methods, devices and systems for improved fabrication and measurement of holographic elements are described. One example method includes directing a reference and an object beam toward a holographic material for formation of a diffraction grating in the holographic material, and blocking one of the reference or the object beams to prevent the beam from reaching the holographic material for at least a portion of time during which the diffraction grating is being formed. During the blockage of the beam, a power level of a diffracted beam associated with the reference or the object beam that is not being blocked is measured. Based on the measured power level, it is then determined whether a particular diffraction grating efficiency is reached. The described techniques enable real-time measurement of diffraction grating efficiency as the grating is being formed and enable improved fabrication of holographic elements hat must meet precise diffraction grating efficiency requirements.

An Electrically Switchable Bragg Grating (ESBG) despeckler device comprising at least one ESBG element recorded in a hPDLC sandwiched between transparent substrates to which transparent conductive coatings have been applied. At least one of said coatings is patterned to provide a two-dimensional array of independently switchable ESBG pixels. Each ESBG pixel has a first unique speckle state under said first applied voltage and a second unique speckle state under said second applied voltage.

The invention relates to a method of creation of three-dimensional alignment patterns that includes providing a layer of optically recordable and polarization sensitive material having a thickness that is greater than, or equal to, a predefined thickness, and concurrently illuminating the optically recordable medium with two coherent beam of same or different polarization with predetermined angle between the beams such that the said beams impinge from the same side or from the opposite sides upon the layer of the recordable material. The invention further relates to polarization volume holograms based on the said alignment patterns and polarization holographic element including a single layer or a stack of several layers of optically recordable materials containing single or multiple polarization volume holograms.

An optical member utilizing light from a point light source is enabled to visually perceive a reproduced optical image with a desired color. An optical modulation device includes an optical member having a light control part to reflect or absorb light in a predetermined wavelength and to pass through light in other than the predetermined wavelength in light in at least a visible light band, in accordance with a reproduction reference image for reproducing an original image, and a light transmissive part to pass through light in at least the visible light range including the predetermined wavelength.